This invention relates to new and useful improvements in a belt drive device wherein the belt is tightened or loosened by means of a belt tightening assembly and although it is designed specifically for use with oil well pumps, nevertheless it will be appreciated that such a drive device may be used in other environments.
Conventionally, standard belt tightening is used but this suffers from several disadvantages when used in oil well pumping environment as the prime mover (engine) is physically shifted back and forth to adjust the belt and this is difficult to do.